yeah just tinker with your truck, it really is the best way to get to know your truck see what things look like and in the future when they break you can identify whats broken because you've seen it or heard in action before. That's how ive done so much to my f150 then when something breaks I just check on here and there's always bound to be someone on here with the same issue and there's always people who know how to fix it.

 

OK, folks.... Taking it to a shop tomorrow to have it put on a machine, I figure that is the best way to go and then I can start from there. Will let you all know what I find out. I am curious about something though. If it is my exhaust backing up into my motor, what could cause that?

 

OK, fellas... Took the truck and had it put on a machine. Mechanic said the IAC and EGR are shot. He thinks that tapping is a valve or piston. But I have read several places where an EGR can cause a valve knock. I am just not sure it is a piston. He wants to do a compression test and see if the piston is totally shot, but with the EGR messed up, would that even be accurate? Any ideas?

 

A compression test is the right thing to do. The bad EGR won't affect it.
If it comes back good then replace the bad parts.

 

I have 2002 Ford F150. Driving one day noticed bad smell like raw gas or rotten eggs or sulfer. AC went warm for minute or 2 then cold. Smell seamed to be going away the about 3 or4 min later happened again but stronger. Then white smoke rolled out from under middle of truck into can. Pulled over and jumped out thought it was on fire because smoke got so heavy. Took awhile for all smoke to clear. Let sit for 20 min waiting on a ride. Friend started truck to see if smell and smoke came back with AC off. Didn't so turned AC on and still no smoke. Said it was ok to drive home 4 miles and I did and nothing happened. Took almost a week for the smell to get ou of can with widows open. Just had checked and only code was for #8 injector or coil, O2 sensor and they said don't do O2 sensors till after the injector and coil because that may be causing the codes for sensors. The above happened 2 days latter before could get it changed. I had also just change 2 of them a month before and it didn't didn't smoke or have that kind of smell. It just smelled like gas when a engine floods. This smell was totally different....Have to fix myself so can't afford a shop. Its me do it or it sits. I have some knowledge and usually can fix my own.